ESPN

77-year-old pro golfer Gary Player didn't do a lick of extra training for his naked debut as the oldest man ever in ESPN's "Body Issue" -- dude says he's been in tip-top shape since birth ... aka the '30s ... yeah, he's that old.

Gary tells TMZ, “I did not do anything special for the shoot" ... other than busting his hump working outdoors on his farm in South Africa everyday for a few months prior to dropping trou for ESPN.

He added, "I was already relaxed, tanned and ready to go.”

Before Gary flashed the family jewels for the shoot 2 weeks ago in Miami ... he says ESPN treated him like a king and provided a serious spread of his fav foods -- including crudités, fresh fruit, hummus, salad, and herbal tea. No wonder GP's in great shape.

As for the whole naked thing, Gary says it didn't bother him one bit -- "I was relaxed and confident in my own skin to do this."

Someone is trying to sell the secret videotape of ESPN's Erin Andrews and it's clear -- there's a pervert on the loose.

We will not publish the video nor did we purchase it. It's a clear invasion of privacy. But this is what we can tell you.

It appears the video was shot from some sort of spy cam. It looks as if someone drilled a small hole in her hotel room from an adjoining room.

The camera is clearly being operated by someone. It follows Erin as she moves about her room.

It looks like a high-end hotel, but Erin's people claim they have no idea where or when it was shot.

It's also clear Erin has absolutely no idea she's being videotaped.